Is it necessary that the store where I buy milk and bread, ground beef and Merlot be able to keep records of my purchases?

QFC's move to require an "Advantage Card" for its cheapest prices irked me for three reasons. First, I do not want another blasted plastic card in my wallet. It already takes too much time to find my insurance card when I go to the doctor.

And the prices I used to get just by walking through QFC's doors are now available only if I present my Advantage Card. If you dare to shop at QFC without the card, you'll pay premium prices.

But most important: To get the cheaper prices, you're required to hand over your name, address, phone number, birth date and marital status. And then every time you check out, the store calculates what you've bought during the year and what you paid for it.

What does the store do with that information?

I called QFC to find out.

I wanted to know what motives, besides giving customers "premium quality and lower prices," had triggered the company to copy Safeway.

I wanted to know why it's necessary to track each customer if QFC doesn't plan to sell -- or release -- the personal information (officials give their "word" that they won't).

The QFC spokesman didn't call back. But here's what he told P-I reporter Jane Hadley last week: "I really don't have any comment on that."

Gee, here's a company that cares so much about its customers that it won't tell them why it's making changes.

So I went to QFC and two other grocery store chains within five miles of my house. I purposely avoided Safeway -- I have the same objections to its "club card." I compared a few prices to see how significant the savings would be if I gave up one more piece of privacy.

Here's what I found last week:

Navel oranges were cheapest at QFC, even without the card.

A gallon of milk at Albertson's was the same price offered QFC customers.

Larry's Market beat QFC's best price, by 2 cents, on a half-flat of fresh strawberries. But if you bought the berries at QFC without the card, you paid $6.02 more.

Baking potatoes were 30 cents a pound cheaper with QFC's card than at Albertson's, but a dime more expensive without the card.

A 12-pack of Fat Tire beer was $1 cheaper at Albertson's than either Larry's Market or the card price at QFC. Without the card, it cost another $2.

I wondered what QFC would say about these prices, which weren't much cheaper than the competition. And I wondered how many customers had found Advantage Card prices to be the same as sale prices at other stores that didn't require a card.

I found a kindred spirit in Jim Vilett, a QFC shopper: "The only advantage I see here is for the corporation," he said. "The customer is not getting anything more than an invasion of privacy forced on them if they want to keep the same sale prices."

When I went to QFC last week and was asked to sign up for the card, I started to give a false name and phone number. But that's a lousy way to protest, and I'd still have to carry the card.